The visual orientation strategies of Mantis religiosa and Empusa fasciata reflect differences in the structure of their visual surroundings

In the present study, peering behaviour, which is used to measure distance by the image motion caused by head movement, is examined in two types of ma ntid. Mantis religiosa inhabits a region of dense grass consisting of unifo rm, generally uniformly aligned, and closely spaced elements and executes s low, simple peering movements. In contrast, Empusa fasciata climbs about in open regions of shrubs and bushes which consist of irregular, variably ali gned and variably spaced elements and it executes comparatively quick, comp lex peering movements. Hence, it seems that in these two species of mantid, the same orientation mechanism has been adapted to the unique structures o f their visual surroundings. Apparently M. religiosa uses motion parallax a nd E. fasciata uses a combination of motion parallax and forward and backwa rd movements (image expansion/contraction over time) to detect object dista nces.